Intracardiac cage and method of delivering same

ABSTRACT

A method of preventing ingress of material into the left atrium of a heart includes providing a delivery sheath, advancing the sheath distal end through an opening between the right atrium and the left atrium of the heart, providing an expandable cage, delivering the expandable cage to the left atrium, and expanding the expandable cage within the left atrium. The expandable cage includes a proximal end, a distal end, and a plurality of supports extending therebetween. The expandable cage also includes a first membrane provided at its proximal end and a second membrane provided at its distal end. The expandable cage has a collapsed configuration so that it can be received within the lumen of the delivery sheath, and an expanded configuration for deployment within the heart. When expanded, the first membrane is positioned at an opening between the left and right atria of the heart, and the second membrane is positioned at the ostium of the left atrial appendage. The first membrane substantially prevents passage of blood between the atria and the second membrane prevents passage of embolic material from the left atrial appendage into the left atrium of the heart.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/846,127, filed Sep. 4, 2015, which is a continuation U.S. applicationSer. No. 13/116,798, filed May 26, 2011, now abandoned, which is acontinuation of U.S. application Ser. No. 11/229,313, filed Sep. 16,2005, now U.S. Pat. No. 7,972,359.

BACKGROUND

1. Field of the Invention

The present invention relates to methods and devices for closing anopening inside of a body, and in some embodiments, to closing, blockingor filtering the ostium of a left atrial appendage, or a septal defect,such as a patent foramen ovale.

2. Description of the Related Art

Embolic stroke is the nation's third leading killer for adults, and is amajor cause of disability. There are over 700,000 strokes per year inthe United States alone. Approximately 100,000 of these are hemorrhagicand 600,000 are ischemic (either due to vessel narrowing or toembolism). A large number of strokes are believed to be caused orrelated to a defect in the heart called a patent foramen ovale, or tothrombus formation due to an irregularity in the heart beat calledatrial fibrillation. Although there are pharmacological therapies forstroke prevention such as oral or systemic administration of warfarin orthe like, these have been found inadequate due to serious side effectsof the medications and lack of patient compliance in taking themedication.

Patent Foramen Ovale

About 50,000 of the ischemic strokes are believed to be caused by apatent foramen ovale. In addition, the risk of recurrent stroke ishigher in patients whose strokes are caused by a patent foramen ovale.

The heart is generally divided into four chambers: the upper two are theleft and right atria and the lower two are the left and rightventricles. The atria are separated from each other by a muscular wall,the interatrial septum, and the ventricles by the interventricularseptum.

Either congenitally or by acquisition, abnormal openings, holes orshunts can occur between the chambers of the heart or the great vessels(interatrial and interventricular septal defects or patent ductusarteriosus and aortico-pulmonary window respectively), causing shuntingof blood through the opening. During fetal life, most of the circulatingblood is shunted away from the lungs to the peripheral tissues throughspecialized vessels and foramens that are open (“patent”). In mostpeople these specialized structures quickly close after birth, butsometimes they fail to close. A patent foramen ovale is a conditionwherein an abnormal opening is present in the septal wall between thetwo atria of the heart. An atrial septal defect is a condition wherein ahole is present in the septal wall between the two atria of the heart.

In contrast to other septal defects which tend to have an opening with agenerally longitudinal axis approximately normal to the septum, a patentforamen ovale tends to behave like a flap valve. Accordingly, the axisof the patent foramen ovale tends to be at an angle, and almost parallelto the septal wall. The patent foramen ovale is a virtual tunnel, longand wide, but not very tall. It is normally closed because the roof andfloor of the tunnel are in contact, but it can open when the pressure inthe right side of the heart becomes elevated relative to the pressure inthe left side of the heart, such as while coughing.

Studies have shown that adults with strokes of unknown origin(cryptogenic strokes) have about twice the rate of patent foramen ovalesthan the normal population. Although there is a correlation betweenstrokes and patent foramen ovales, it is currently unknown why thiscorrelation exists. Many people theorize that blood clots and plaquethat have formed in the peripheral venous circulation (in the legs forexample) break off and travel to the heart. Normally, the clots andplaque get delivered to the lungs where they are trapped and usuallycause no harm to the patient. Patients with a patent foramen ovale,however, have a potential opening through which the clots or plaque canpass from the venous circulation and into the arterial circulation. Theclots or plaque can then travel to the brain or other tissues to cause athromboembolic event like a stroke. The clots may pass to the arterialside when there is an increase in the pressure in the right atrium. Thenthe clots travel through the left side of the heart, to the aorta, andthen to the brain via the carotid arteries where they cause a stroke.

Recent studies also suggest a higher incidence of patent foramen ovalein patients suffering from migraine headache, and particularly those whoexperience aura in association with their migraines, than in the generalpopulation. It is theorized that closure of PFO will substantiallyimprove or even cure migraine in these patients, and trials underwaysuggest that for some patients their migraine was resolved subsequent toclosure of their PFO. It has been suggested that migraine could berelated to passage through a PFO of gas microemboli, thrombi, orvasoactive chemicals, whereas normally these substances pass through thelungs where they are filtered out or otherwise deactivated.

Previously, patent foramen ovale have required relatively extensivesurgical techniques for correction. To date the most common method ofclosing intracardiac shunts, such as a patent foramen ovale, entails therelatively drastic technique of open-heart surgery, requiring openingthe chest or sternum and diverting the blood from the heart with the useof a cardiopulmonary bypass. The heart is then opened, the defect issewn shut by direct suturing with or without a patch of syntheticmaterial (usually of Dacron, Teflon, silk, nylon or pericardium), andthen the heart is closed. The patient is then taken off thecardiopulmonary bypass machine, and then the chest is closed.

In place of direct suturing, closure of a patent foramen ovale by meansof a mechanical prosthesis has also been disclosed. A number of devicesdesigned for closure of interatrial septal defects have been used tocorrect patent foramen ovale. Although these devices have been known toeffectively close other septal defects, there are few occlusion devicesdeveloped specifically for closing patent foramen ovale.

Atrial Fibrillation

The most common cause of embolic stroke emanating from the heart isthrombus formation due to atrial fibrillation. Approximately 80,000strokes per year are attributable to atrial fibrillation. Atrialfibrillation is an arrhythmia of the heart that results in a rapid andchaotic heartbeat that produces lower cardiac output and irregular andturbulent blood flow in the vascular system. There are over five millionpeople worldwide with atrial fibrillation, with about four hundredthousand new cases reported each year. Atrial fibrillation is associatedwith a 500 percent greater risk of stroke due to the condition. Apatient with atrial fibrillation typically has a significantly decreasedquality of life due, in part, to the fear of a stroke, and thepharmaceutical regimen necessary to reduce that risk.

For patients who develop atrial thrombus from atrial fibrillation, theclot normally occurs in the left atrial appendage (LAA) of the heart.The LAA is a cavity which looks like a small finger or windsock andwhich is connected to the lateral wall of the left atrium between themitral valve and the root of the left pulmonary vein. The LAA normallycontracts with the rest of the left atrium during a normal heart cycle,thus keeping blood from becoming stagnant therein, but often fails tocontract with any vigor in patients experiencing atrial fibrillation dueto the discoordinate electrical signals associated with AF. As a result,thrombus formation is predisposed to form in the stagnant blood withinthe LAA.

Blackshear and Odell have reported that of the 1288 patients withnon-rheumatic atrial fibrillation involved in their study, 221 (17%) hadthrombus detected in the left atrium of the heart. Blackshear J L &Odell J A., Appendage Obliteration to Reduce Stroke in Cardiac SurgicalPatients With Atrial Fibrillation, Ann. Thorac. Surg.,1996.61(2):755-59. Of the patients with atrial thrombus, 201 (91%) hadthe atrial thrombus located within the left atrial appendage. Theforegoing suggests that the elimination or containment of thrombusformed within the LAA of patients with atrial fibrillation wouldsignificantly reduce the incidence of stroke in those patients.

As discussed above, pharmacological therapies for stroke prevention suchas oral or systemic administration of warfarin or the like have beeninadequate due to serious side effects of the medications and lack ofpatient compliance in taking the medication. Invasive surgical orthorascopic techniques have been used to obliterate the LAA, however,many patients are not suitable candidates for such surgical proceduresdue to a compromised condition or having previously undergone cardiacsurgery. In addition, the perceived risks of even a thorascopic surgicalprocedure often outweigh the potential benefits. See Blackshear & Odell;see also Lindsay B D, Obliteration of the Left Atrial Appendage: AConcept Worth Testing, Ann. Thorac. Surg., 1996.61(2):515.

Despite the various efforts in the prior art, there remains a need for aminimally invasive method and associated devices for reducing the riskof thrombus formation in the left atrial appendage.

SUMMARY

In one embodiment, a method of preventing ingress of material into theleft atrium of a heart includes: providing a delivery sheath having asheath proximal end, a sheath distal end, and a lumen extendingtherethrough, to the right atrium of the heart; advancing the sheathdistal end through an opening between the right atrium and the leftatrium; providing an expandable cage, having a proximal end, a distalend, a plurality of supports extending therebetween, a first membraneprovided at the proximal end, and a second membrane provided at thedistal end, the expandable cage having a collapsed configuration to bereceived within the lumen of the delivery sheath, and an expandedconfiguration for deployment within the heart; delivering the expandablecage to the left atrium of the heart through the delivery sheath; andexpanding the expandable cage within the left atrium, the expandablecage when expanded positioning the second membrane at the ostium of theleft atrial appendage, wherein the second membrane prevents passage ofembolic material from the left atrial appendage into the left atrium,and positioning the first membrane at an opening between the left atriumand a right atrium of the heart, where the first membrane substantiallyprevents passage of blood between the atria.

The opening can be a natural opening, and the opening can be formed bypiercing the atrial septum. In one embodiment, the opening is a patentforamen ovale or a septal defect.

The cage can be self expanding, and can be expanded by retracting thedelivery sheath proximally. In one embodiment, the delivering stepincludes pulling the delivery sheath proximally with respect to theexpandable cage prior to said expanding step. In another embodiment, thedelivering step includes pushing the expandable cage past the sheathdistal end prior to said expanding step. In another embodiment,delivering the expandable cage includes positioning the cage distal ofthe distal end prior to said expanding step.

The method can further include verifying the position of the expandablecage within the left atrium, wherein said verifying is performed priorto said expanding step, repositioning said cage within the left atrium,and/or retrieving said cage from the left atrium.

In another embodiment of the present invention a method of preventingingress of material to a chamber of a heart includes: providing anexpandable cage to a chamber of a heart, wherein said chamber has atleast two openings, and wherein said expandable cage comprises aproximal end, a distal end, a plurality of supports extendingtherebetween, and at least one membrane, the expandable cage having acollapsed configuration for delivery to the heart, and an expandedconfiguration for deployment within the heart; and expanding saidexpandable cage within the chamber of the heart, wherein said at leastone membrane is positioned at one of said at least two openings of thechamber to prevent ingress of material into the chamber.

One of said at least two openings can be an ostium to a left atrialappendage, a patent foramen ovale, or a septal defect. The membrane canfilter blood from a left atrial appendage and/or substantially preventblood flow from a right atrium into a left atrium the heart.

In another embodiment, an expandable cage for preventing ingress ofmaterial to a chamber of a heart includes: a frame including a proximalend, a distal end, and a plurality of supports extending therebetween,wherein said cage has a collapsed configuration for delivery to achamber of the heart, and an expanded configuration for deploymentwithin the heart; and at least one membrane provided at at least one ofsaid proximal and said distal ends, wherein a length between saidproximal and distal ends when at least partially expanded generallyapproximates the distance between an ostium of a left atrial appendageand a septum of the heart.

The at least one membrane can include a proximal membrane provided atsaid proximal end and a distal membrane provided at said distal end. Theat least one membrane can have a diameter corresponding to thedimensions of a patent foramen ovale or a diameter corresponding to thedimensions of an ostium of a left atrial appendage. In anotherembodiment, the proximal end includes supports that extend proximally,distally, and proximally from an apex to a proximal hub.

In yet another embodiment of the present invention, a system forpreventing ingress of material to a chamber of a heart includes andexpandable cage; and a transseptal sheath for delivering the expandablecage to the chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an anterior illustration of a heart, with the proximalportions of the great vessels;

FIG. 1B is a partial cross-sectional view of the heart of FIG. 2;

FIG. 2 is a schematic, partial cross-sectional view of an intracardiaccage implanted in a chamber of a heart.

FIG. 3 is a perspective view of an intracardiac cage in accordance withone embodiment of the present invention;

FIG. 3A is a side elevational view of the intracardiac cage of FIG. 3;

FIG. 3B is an end view taken along the line 3B-3B of FIG. 3A;

FIG. 3C is one embodiment of an intracardiac cage having branchedportions;

FIG. 3D is one embodiment of an intracardiac cage having serpentinespring portions;

FIG. 3E is one embodiment of the end portion of an intracardiac cage;

FIG. 3F is a top view of a fracturable support;

FIG. 3G is a side view of the fracturable support of FIG. 3F;

FIG. 4 is a partial cross-sectional view of an intracardiac cageaccording to another embodiment of the present invention;

FIGS. 5-7 are perspective views of an intracardiac cage according toadditional embodiments of the present invention;

FIGS. 8-9 are perspective views of a delivery system for delivering theintracardiac cage of FIGS. 3-7 to a desired location within the heart;

FIG. 10 is a detailed view of the distal end of the delivery system ofFIG. 9;

FIG. 11 is a partial cross-sectional view of the axially moveable coreof FIGS. 8-10;

FIG. 11A is a cross-sectional view taken along line 11A-11A of FIG. 11;

FIG. 12 is a perspective view of an intracardiac cage coupled to theaxially moveable core of FIG. 11;

FIGS. 13A-13C are perspective views of a transseptal sheath inaccordance with embodiments of the present invention;

FIG. 14 is a perspective view of a dilator in accordance with oneembodiment of the present invention;

FIG. 14A is a detailed view of the distal end of the dilator of FIG. 14;and

FIGS. 15A-15N are schematic, partial cross-sectional views showing thedelivery and deployment of an intracardiac cage to the left atrium of apatient's heart.

DETAILED DESCRIPTION

Some embodiments of the present invention are described primarily in thecontext of a left atrial appendage, septal defect or patent foramenovale closure device or procedure; however, the devices and methodsherein are readily applicable to a wider variety of closure orattachment procedures, and all such applications are contemplated by thepresent inventors. Vascular procedures such as patent ductus arteriosisclosure, isolation or repair of aneurysms, or occlusion of vessels,ducts, or conduits, may also be accomplished using the devices asdescribed herein. A variety of other tissue openings, lumens, holloworgans and surgically created passageways may be closed in accordancewith the preferred embodiments. Closures and repairs described hereinmay be accomplished using catheter based interventional methods orminimally invasive surgical methods. Adaptation of the devices andmethods disclosed herein to accomplish procedures such as the foregoingwill be apparent to those of skill in the art in view of the disclosureherein.

The Heart

FIG. 1A is a heart 100 and certain portions including the left ventricle102, the left atrium 104, the left atrial appendage 106, the pulmonaryartery 108, the aorta 110, the right ventricle 112, the right atrium114, and the right atrial appendage 116. The left atrium 104 is locatedabove the left ventricle 102 and the two are separated by the mitralvalve (not illustrated).

FIG. 1B is a partial cross-sectional view of the heart 100 of FIG. 1Awith additional features shown. Deoxygenated blood generally enters theright atrium 114 from the upper portion of the body via the superiorvena cava 202 and from the lower portion of the body via the inferiorvena cava 204. The blood is pumped from the right atrium 114 into theright ventricle 112 through the tricuspid valve 206 and then to thelungs (not shown) through the pulmonary valve 208 and pulmonary arteries108.

Oxygenated blood returns to the heart 100 from the lungs via thepulmonary veins 210, which direct the blood into the left atrium 104. Asthe heart 100 pumps, the oxygenated blood passes from the left atrium104 into the left ventricle 102 via the mitral valve 212. Blood exitsthe left ventricle 102 via the aortic valve 214 and aorta 110, whichdistributes the oxygenated blood to the body via the circulatory system.

A septum 216 separates the left side of the heart 100 from its rightside, and prevents blood from flowing directly therebetween. Inparticular, an interatrial septum (not shown) separates the right atrium114 from the left atrium 104, and an interventricular septum separatesthe right ventricle 112 from the left ventricle 102. The interatrialseptum and interventricular septum are sometimes referred to as theatrial septum and ventricular septum, respectively.

In some clinical situations there is a hole or defect in the septum 216of the heart 100, which allows blood to flow directly from the rightatrium 114 to the left atrium 104, or from the right ventricle 112 tothe left ventricle 102. It is often clinically desirable to seal orclose off such holes or defects. In addition, in patients that sufferfrom atrial fibrillation, it is often desirable to seal, close off,block, or filter the opening between the left atrium 104 and the leftatrial appendage 106 of the heart 100.

Intracardiac Cages

Embodiments of structures suitable for blocking an opening to a chamberof the heart are illustrated in FIGS. 2-7. It should be understood thatalthough the embodiments described herein may be referred to asblocking, the same embodiments are also suitable for filtering, sealing,closing off, or plugging, both totally or partially.

FIG. 2 illustrates one embodiment of an intracardiac cage 300 implantedin a left atrium 104 of a patient. The cage 300 has a proximal end 302positioned against the atrial septum 216, and a distal end 304positioned against the ostium of the left atrial appendage 106. A firstmembrane 500A is provided at the proximal end of the cage 300 to createa barrier to the ingress of material, such as particles or fluid orboth, into the left atrium 104 through any opening that may be locatedin the atrial septum 216, such as a septal defect, patent foramen ovale,or a puncture opening used for accessing the left atrium 104. Inaddition, the intracardiac cage 300 may be used to close multiple atrialseptal defects occurring in a patient's heart. A second membrane 500B isprovided at the distal end of the cage 300 to create a barrier to theingress of material, such as particles or fluid or both, into the leftatrium 104 from the left atrial appendage 106.

The cage 300 may have any suitable configuration adapted to span thedistance between the septum 216 and the atrial appendage 106 andposition the membranes 500A and 500B across an opening in the septum 216and the ostium of the atrial appendage 106. Although two membranes 500A,500B are illustrated on the cage 300, it will be appreciated that onlyone membrane may be used, if desired, to provide a barrier to either aseptal opening or the atrial appendage, or more than two membranes maybe used to prevent ingress of material from other openings into thechamber. In another embodiment, the cage 300 does not include amembrane. Instead, the cage itself acts as a barrier to substantiallyprevent ingress of particles, fluids, or both into the left atrium.

The cage 300 is preferably expandable within the left atrium to providesufficient force to hold the membranes 500A and 500B against therespective openings. In one embodiment, the cage 300 is self-expanding,such that in the configuration shown in FIG. 2, the cage 300 is in amostly, but not completely, expanded configuration, to hold the cage inplace. In other embodiments, the cage 300 may be manually expanded, suchas by inflation of a balloon or other mechanism, with the cage 300locking itself in the desired configuration within the heart.

In one embodiment, any of a variety of active expansion devices are usedto expand the cage 300 within a patient. For example, telescoping tubescan be used to expand the cage 300. An inner tube can be positioned incontact with the distal end of a cage 300 and an outer tube can bepositioned in contact with the proximal end of the cage 300. By movingthe outer tube distally with respect to the inner tube, distal force canbe applied to the proximal end of the cage 300, thereby causing the cage300 to change its shape from reduced-diameter configuration to anexpanded-diameter configuration.

The amount of cage 300 expansion can be controlled by any of a varietyof mechanisms, such a lock placed on either or both of the telescopingtubes to fix its position when the tubes achieve a predetermined ordesired separation. In addition, a ratchet can be used to fix theseparation between the telescoping tubes. Telescoping tubes and otherembodiments of cage 300 expansion devices are described in U.S.application Ser. No. 10/426,107, filed Jul. 30, 2002, which isincorporated by reference herein. One of skill in the art willappreciate that although the expansion devices and structures describedin the aforementioned application are configured for an implantabledevice for placement within a left atrial appendage, these teachings canreadily be applied to a cage as described herein for placement within anatrium. Similarly, the devices and methods described in the otherpatents and applications incorporated by reference hereinbelow can alsobe adapted to the expandable cage described herein. The cage 300 in oneembodiment has a length between the proximal and distal ends of about 2cm to about 10 cm, more preferably about 5 cm to about 7 cm, tocorrespond to the size of the left atrium 104.

An intracardiac cage 300 in accordance with one embodiment of thepresent invention is illustrated in FIGS. 3-3F, without showing themembranes 500A and 500B. The cage 300 has a proximal end 302, a distalend 304, and a longitudinal axis extending therebetween. A plurality ofsupports 306 extend between a proximal hub 308 and a distal hub 310. Thecage 300 can include at least two or three supports 306, and in someembodiments, includes at least about ten supports 306. In oneembodiment, sixteen supports 306 are provided. In another embodimentillustrated in FIG. 3C, the supports 306 are branched into branches 307to provide mechanical coverage at the ends 302, 304 of the cage 300 andreduce the mechanical coverage in the non-barrier, central, or midportion of the cage 300. The branches 307 can be provided at proximalend 302, the distal end 304, or both ends 302, 304 of the cage 300.

In another embodiment illustrated in FIG. 3D, the supports 306 includecurves 309, such as serpentine curves or s-shaped curves, to provide anoverall deployed length that can vary to fit a variety of atrium lengthsyet collapse into a delivery catheter. The curves 309 can be positionedat any one or a combination of the proximal end 302, distal end 304, ormid portion of the cage 300. In one embodiment, the tissue-contactingsurface of the curves 309 is formed within the outer surface defined bythe cage 300. The curves 309 of the cage 300 provide lengthadjustability during cage 300 deployment. The supports 306 can bedeployed substantially in contact with the inner surface of the atriumto reduce blood flow disturbances. Blood flow disturbances can be acause of thrombus formation and thrombus can embolize, potentiallycausing infarcts and/or strokes.

The precise number and configuration of supports 306 can be modifieddepending upon the desired physical properties of the cage 300, as willbe apparent to those of skill in the art in view of the disclosureherein without departing from the present invention. The cage 300 canalso include an occluding member (not shown) and any of a variety ofstabilizing members, such as those described in U.S. application Ser.No. 09/435,562, filed Nov. 8, 1999, and U.S. application Ser. No.10/033,371, filed Oct. 19, 2001, published as U.S. Publication No.2002/0111647, which are incorporated by reference. The supports 306 aregenerally sufficiently spaced apart from one another to allow blood toflow between them.

In another embodiment, the proximal hub 308, distal hub 310, or both,and the associated supports 306 can be shaped as shown in FIG. 3E, inwhich the hub 308, 310 is at least partially recessed. For example, thehub 308, 310 can be recessed relative to the surface defined byprojecting the supports in a continuous curve 311, such as that shown asthe dashed line in FIG. 3E. This recessing either or both of the hubs308, 310 may be employed with any of the embodiments shown herein. Thehub 308, 310 can be recessed so that when deployed, it does not causeirritation or tissue damage to the heart.

Each support 306 can include a proximal spoke portion 312, a distalspoke portion 314, and an apex 316. Each of the proximal spoke portion312, distal spoke portion 314 and apex 316 can be a region on anintegral support 306, such as a continuous rib or frame member whichextends in a generally curved configuration as illustrated, with aconcavity facing towards the longitudinal axis of the cage 300. Adistinct point or hinge at apex 316 can or can not be provided.

The cage 300 may be reduced in diameter to a reduced or collapsedconfiguration for transluminal delivery to the heart, as will bedescribed in greater detail below. Once delivered to the heart, the cage300 diameter can be expanded to an expanded configuration for placementand securement at the desired location within the heart 100. In oneembodiment, the cage 300 may be self-expanding, with supports made of asuperelastic material such as nickel titanium alloy or nitinol. Tocollapse the cage 300, the supports 306 may be extended axially to agenerally linear configuration, with the distance between the proximaland distal hubs 308, 310 increasing. In another embodiment, the cage 300may be collapsed to its reduced configuration while maintaining thedistance between the proximal and distal hubs 308, 310 substantiallyconstant, such as by folding the supports 306 upon themselves orotherwise collapsing the supports 306 while holding the relativeposition of the proximal and distal ends 302, 304. Even more preferably,the supports 306 may not only collapse upon themselves, but the distancebetween the proximal and distal hubs 308, 310 may decrease when the cage300 is moved to its collapsed configuration, such as by pulling thedistal end 304 toward the proximal end 302, or pushing the proximal end302 toward the distal end 304, or both. Then, when the cage 300 expands,it expands not only radially outwardly, but also axially to increase thedistance between the proximal and distal hubs 308, 310. Such anembodiment may facilitate placement of the cage 300 within a chamber ofthe heart 100, as described below.

Some of the supports 306, and in some cases each support 306, can beprovided with one or two or more anchors or barbs 318 to help secure oranchor the cage 300 at the desired location within the heart 100. In theconfiguration illustrated in FIG. 3, with the cage 300 in its enlargedorientation, each of the barbs 318 projects generally radially outwardlyfrom the longitudinal axis, and is inclined in the proximal direction.One or more barbs 318 may also be inclined distally, orthogonally,perpendicularly, inwardly, outwardly, and/or to the side, as may bedesired by the particular clinical use. In a preferred embodiment enoughbarbs 318 are provided to prevent the cage from rotating relative to theatrial wall. For example, in one embodiment, at least one barb 318 isdirected in each of a proximal, distal, and transverse direction withrespect to a support 306 to prevent the cage 300 from rotating relativeto the atrial wall. In one embodiment, the cage 300 includes three barbs318. In another embodiment, the cage 300 includes four barbs. In oneembodiment, the barbs 318 and corresponding support 306 are cut from asingle ribbon, sheet or tube stock and the barb 318 inclines radiallyoutwardly at approximately a tangent to the curve formed by the support306. In one embodiment the cage 300 includes no barbs 318 at all.

The term “barb” is a broad term intended to have its ordinary meaning.The term “barb” can include any of a variety of anchors, locks,adhesives, clips, clamps, coils, springs, and/or hooks known to those ofskill in the art. The barb can be any device that holds, secures, fixes,locks, and/or maintains the position of an implantable device, such asan intracardiac cage 300, either partially, substantially, or totally,within the heart. In some embodiments, the barbs are projections that donot come to a point, such as a catch and release hook. Barbs may havetraumatic or atraumatic tips, or a combination thereof. In addition, thebarbs can engage, penetrate, pierce, pinch, press, and/or grasp thetissue at the inside wall of the heart.

In some embodiments, the cage 300 can be deployed or recovered using adelivery system, as described in greater detail below. Cage 300 recoverycan be facilitated by the anchor or barb design. For example, theanchors or barbs can pronate such that they do not ‘ catch’ on adelivery catheter during cage recovery or implant delivery. In oneembodiment barbs move into the planes of the supports during withdrawalof the cage into a catheter, thereby preventing the barbs fromcontacting the distal end of the catheter and impeding withdrawal of thecage into the catheter. In another embodiment, the barbs move inward tothe planes of the supports during withdrawal of the cage 300 into acatheter. Implantable devices including pronating anchors and barbs aredisclosed in U.S. application Ser. No. 10/838,710, filed May 4, 2004,which is incorporated by reference herein.

In some embodiments the barbs allow tissue ingrowth, and in otherembodiments they prevent tissue ingrowth. In one embodiment, the support306 has a center portion that is fractureable, which permits the cage300 to separate into two portions. Cage fracture may be desirable forhearts which become enlarged, or which contract in overall size, overtime. In such embodiments, the barbs preferably promote tissue ingrowth,which allows permanent anchoring of each cage 300 portion within theheart. In one such embodiment, the barbs 318 are located only at theproximal and distal ends 302, 304 of the cage 300, and not in the centerportion 313. One embodiment of a fracturable support 306 is illustratedin FIGS. 3F and 3G. In one embodiment, the fracturable support 306 hastwo atraumatic loop ends 313 that are coupled to one another with arivet 315. The rivet 315 can be made from a bioresorbable material sothat it dissolves over time.

Anchoring of the cage 300 relative to the atrial wall may be desirableto prevent cardiac tissue irritation, erosion, or damage; to preventirritation or disruption of conduction pathways in the heart tissue, toorient supports in relation to blood flow pathways such as the pulmonaryvein or the mitral valve.

The cage 300 illustrated in FIG. 3 may be constructed in any of avariety of ways, as will become apparent to those of skill in the art inview of the disclosure herein. In one method, the cage 300 isconstructed by laser cutting a piece of tube stock to provide aplurality of axially extending slots in-between adjacent supports 306.Similarly, each barb 318 can be laser cut from the corresponding support306 or space in-between adjacent supports 306. Generally axiallyextending slots 320 separate adjacent supports 306 and end a sufficientdistance from each of the proximal end 302 and distal end 304 to createa proximal hub 308 and a distal hub 310 to which each of the supports306 is attached. In this manner, an integral cage 300 is formed.

Alternatively, each of the components of the cage 300 may be separatelyformed and attached together such as through soldering, brazing, heatbonding, adhesives, and other fastening techniques which are known inthe art. Another method of manufacturing the cage 300 is to laser cut aslot pattern on a flat sheet of appropriate material, such as a flexiblemetal or polymer. The flat sheet may thereafter be rolled about an axisand opposing edges bonded together to form a tubular structure. Inanother embodiment, the cage 300 is manufactured by braiding astructure, such as wire filament, into a cylindrical configuration andcrimping the braided ends into radiopaque tubes. Such devices andmethods are described in U.S. Pat. No. 6,325,815, which is incorporatedby reference herein.

The apex portion 316, which can also carry a barb 318 may be advancedfrom a low profile, compressed, or reduced-diameter orientation (notshown) in which each of the supports 306 extend generally parallel tothe longitudinal axis, to an implanted, expanded or enlarged-diameterorientation as illustrated, in which the apex 316 and its barb 318 arepositioned radially outwardly from the longitudinal axis. The support306 may be biased towards the enlarged orientation, or may be advancedto the enlarged orientation under positive force following positioningwithin a desired tubular anatomical structure, in any of a variety ofmanners.

A cross-sectional view of another embodiment of an intracardiac cage 300is shown in FIG. 4. The cage 300 preferably is available in a range ofsizes to accommodate the anatomy of a patient's heart 100. The cage 300preferably includes a frame 402 and a membrane (not shown) on theproximal face or end 302 of the cage 300 and/or distal face or end 304of the cage 300. The frame 402 can be constructed of self-expandingnitinol supports 306. The membrane preferably is constructed of a fabriccovering, such as one made of expanded polytetrafluoroethylene (ePTFE),or an ePTFE/polyethylene (PE) laminate. To attach the membrane to theframe 402, a PE mesh preferably is placed against the supports 306, withone sheet of ePTFE preferably placed over the PE mesh and another sheetof ePTFE preferably placed on an opposite side of the supports 306. Themembrane preferably is heated on both sides causing the PE to melt intoboth sheets of ePTFE, thereby surrounding a portion of the frame 402.The nitinol supports 306 allow the cage to self-expand in the desiredportion of the heart 100, and can be expanded such that the membranecovers, blocks, filters, contacts, engages, or applies pressure to adesired anatomical surface, area, region, orifice, ostium, hole ordefect. The ePTFE/PE lamination is generally partially porous, andfacilitates rapid endothelialization and healing.

The membrane can include implant grade filter or barrier materials suchas polyester, polyurethane, polyethylene, expandedpolytetrafluoroethylene (ePTFE), polypropylene mesh, metal mesh,including Nitinol, stainless steel, and other metals, and other filteror barrier materials as are commonly known in the art. The membrane caninclude an impervious film, and in some cases can have openings toenhance fluid flow therethrough. The openings can be created by any of avariety of methods, including laser drilling, piercing, etc. Themembrane can be a woven, non-woven, knitted, cast, spun, electrospun,laminated, blow-molded, or otherwise fabricated material.

The membrane can be attached to the supports 306 by heat-fusing, with orwithout an intermediate adhesive layer, by encircling supports andattaching the membrane to itself using any of a variety of techniques,such as heat fusing, solvent welding, ultrasonic welding, by usingadhesives, by mechanical interlock, or by other means as are known inthe art.

The membrane can be configured to provide a impervious barrier functionto some or all of any substances desired, such as substances thought tobe a significant causative factor in stroke or migraine, including butnot limited to particles, emboli, thromboemboli, gas bubbles, vasoactivechemicals, neuromediators, or other substances normally filtered by orotherwise deactivated by the lungs. The membrane can be configured tofilter some or all of such substances. The membrane can be configured tode-activate or remove from the bloodstream some or all of any substancesthought to be a significant causative factor in stroke or migraine,including but not limited to those listed above. One or more membranesmay be applied to the supports 306, and each membrane applied may havedifferent barrier, filter, or de-activation characteristics, and anysingle membrane may have regions with differing barrier, filter, orde-activation characteristics.

As shown in FIG. 4, the cage 300 preferably extends from a proximal endor hub 302 to a distal end or hub 304. In some embodiments, the proximalhub 302 is coupled with a crosspin 404A. In some embodiments the distalhub 304 is coupled with a slider assembly 406, as described in U.S.application Ser. No. 10/642,384, filed Aug. 15, 2003, which isincorporated by reference in its entirety. The distal hub 304 preferablyis coupled with an implant plug 408. In one embodiment, the implant plug408 comprises an atraumatic tip, such that contact between theatraumatic tip and the inside surface of the heart 100 does not causesubstantial damage or trauma to the heart 100. The distal hub 304 mayalso be used to extend into the left atrial appendage to hold the cagein place. A crosspin 404B secures the implant plug 408 to the distal endor hub 304. The cage 100 preferably is expandable and collapsible, asdescribed above, and can include anchors 318 that extend from the frame402 when the cage 300 is expanded, as described above.

FIGS. 5-7 illustrate additional embodiments of an intracardiac cage 300in accordance with additional embodiments of the present invention. Thecage 300 may be provided with a barrier 500, such as a mesh or fabric ashas been previously discussed. The barrier 500 may be provided on onlyone half or hemisphere, such as proximal face 302 as illustrated, onboth faces (not shown), or may be carried by the entire cage 300 fromits proximal end 302 to its distal end 304 provided the barrier hassuitable flow properties for the chosen configuration. The barrier 500may be secured to the radially inwardly facing surface of the supports306, as illustrated in FIG. 6, or may be provided on the radiallyoutwardly facing surfaces of the supports 306, or both.

Another embodiment of an intracardiac cage 300 is illustrated in FIG. 7,in which the apex 316 is elongated in an axial direction to provideadditional contact area between the cage and the wall of the anatomicalstructure into which it is to be inserted. In this embodiment, one ortwo or three or more anchors or barbs 318 may be provided on eachsupport 306, depending upon the desired clinical performance. The cage300 illustrated in FIG. 7 may also be provided with any of a variety ofother features discussed herein, such as a partial or complete barrier500. In addition, the cage 300 of FIG. 7 may be enlarged or reduced indiameter using any of the techniques disclosed elsewhere herein.

The intracardiac cage 300 can be any of a variety of shapes, includingspherical, elliptical, hexagonal, octagonal, or any other symmetric orasymmetric shape. The cage 300 can have an s-shaped, c-shaped, and/or au-shaped portion. The cage 300 can act like a spring and spring into itsexpanded shape when released from the delivery system, as described ingreater detail below. The cage supports can be oriented substantiallyaxially relative to a line from hub to hub or can have a spiralorientation relative to this line.

Delivery Systems

The intracardiac cage 300 as described above may be delivered to theleft atrium 104 of a patient by any suitable method. In one embodiment,a transseptal sheath, such as described below, may be delivered into theleft atrium 104 through the septum 216 from the right atrium 114, with aself-expanding cage 300 collapsed within the transseptal sheath at itsdistal end. The transseptal sheath may pass through or pierce anysuitable portion of the septum 216, including the fossa ovalis, a septaldefect, the patent foramen ovale, or any other portion, including ahealthy portion, of the septum 216. A distal end of the sheath may bepositioned at the ostium of or within the left atrial appendage 106. Apush rod may be inserted into the transseptal sheath to engage theproximal end of the cage 300. In one embodiment, the push rod mayreleasably engage the cage 300, such as with a threaded connection,simple contact, or other mechanism. With the distal end of thetransseptal sheath, and correspondingly, the distal end 304 of the cage300, at the ostium of or within the left atrial appendage 106, thetransseptal sheath may be retracted proximally, while maintaining thepush rod against the cage 300. As the transseptal sheath is retracted,the cage 300 is exposed and self-expands to engage against the walls ofthe left atrium 104. In one embodiment, the transseptal sheath iswithdrawn until the tip of the sheath is barely (e.g., 1-2 mm) withinthe left atrium, and thereafter the push rod is advanced to fully deploythe cage. At this point the transseptal sheath is fully withdrawn fromthe septum until the tip of the sheath is within the right atrium. Inone embodiment, the push rod is hollow to allow radiopaque contrast dyeinjections and associated physician evaluation before, during, and aftercage deployment.

In one embodiment, the push rod is hollow, and a core extends throughthe push rod and releasably engages the distal end 304 of the cage 300.When the cage 300 is collapsed in the transseptal sheath, the distancebetween the proximal and distal ends 302, 304 of the cage 300 may bereduced relative to its expanded configuration by relative movement ofthe core and the push rod. Then, when the transseptal sheath isretracted from the cage 300, the core and the push rod may be movedrelatively to cause the proximal and distal ends 302, 304 of the cage300 to move away from each other, relieving stress in the cage 300 andallowing it to expand not only radially but also axially. This causesthe cage 300 to expand outwardly against the septum 216 and the ostiumof the left atrial appendage 106, providing a holding force to hold themembranes 500A, 500B in position.

A delivery system 800 for delivering an intracardiac cage 300,particularly the cage 300 shown in FIG. 4 above, in accordance withanother embodiment of the present invention is illustrated in FIGS.8-12. Referring to FIGS. 8 and 9, the delivery system 500 preferablyincludes a peel-away sheath 802, a recapture sheath 804, a deploymentcatheter 806, and an axially moveable core 808, each described furtherbelow. FIG. 8 illustrates the delivery system 800 without a loadingcollar, and FIG. 9 illustrates the deployment system with a loadingcollar 900. In addition, the delivery system 800 of FIG. 9 is shown withthe system 800 operably connected to an intracardiac cage 300.

The deployment catheter 806 preferably comprises a deployment handle 810and a multi-lumen shaft 812. As shown in FIGS. 8 and 9, the deploymenthandle 810 preferably comprises a control knob 814, a release knob 816,a proximal injection port 818 and a distal injection port 820. Themulti-lumen shaft 812 preferably comprises a four-lumen shaft shown inFIG. 8A. The multi-lumen shaft 812 preferably comprises a core lumen 822for holding an axially moveable core 808, a control line lumen 824 andtwo proximal injection lumens 826 in communication with the proximalinjection port 818.

An axially moveable core 808 preferably extends from the deploymenthandle 810 through the core lumen 822 of the catheter 806 and couplesthe intracardiac cage 300 (not shown) to the delivery system 800 with acoupling (not shown). The coupling may be any coupling known to those ofskill in the art, including a threaded portion, a lock, an interface, agrip, slider assembly 406, or any other coupling. A control line (notshown), which may be a pull wire, preferably extends through the controlline lumen 824 and preferably couples the proximal hub 308 of theintracardiac cage 300 to the deployment handle control knob 814,allowing for cage 300 expansion and collapse. The control linepreferably extends around a portion of the axially movable core 808 nearthe proximal hub 308 of the cage 300, and is coupled to the cage 300 bya crosspin 404, as shown in greater detail in FIG. 10.

As shown in FIG. 10, the deployment catheter 806 preferably comprises aflexible catheter section 828 at its distal end, which in someembodiments is a spiral cut tubular section housed in a polymer sleeve830. The flexible catheter section 828 may be coupled to the distal endof the multi-lumen shaft 812.

As shown in FIGS. 10 and 11, the axially moveable core 808 preferablyincludes a hollow proximal shaft 832 and a hollow distal shaft 834coupled together with a flexible hollow core section 836, all of whichare co-axially aligned and connected. In one embodiment, the proximalend of the distal shaft 834 is attached to the distal end of theflexible core section 836, and the proximal end of the flexible coresection 836 is attached to the distal end of the proximal shaft 832. Insome embodiments, the flexible core section 836 has a spring coilsection 840 housed in a polymer sleeve 842, the spring coil section 840preferably coupled with the shafts 832, 834 at first and second ends844, 846.

The axially moveable core 808 preferably is disposed within thedeployment catheter 806 such that the flexible core section 836 may belinearly co-located with the flexible catheter section 828 at a distalportion 848 of the delivery system 800 during appropriate times during aprocedure, as shown in FIG. 10. When the flexible core section 836 isaligned and linearly co-located with the flexible catheter section 828,the sections 828, 836 preferably cooperate to form a delivery systemflexible segment 850. As shown in FIGS. 8-10, the delivery systemflexible segment 850 preferably is located toward a distal end 848 ofthe delivery system 800.

In one embodiment, shown in FIG. 11, the distal shaft 834, flexible coresection 836, and proximal shaft 832 are attached by welding. Smallwindows 852 may be provided to allow welding materials to flow betweenthe shafts 832, 834, 836 and provide stronger bonding therebetween. Inanother embodiment, solder, glue, or press-fitting is used to attach theshafts 832, 834, 836 to one another, as is well known to those of skillin the art. In another embodiment, the shafts 832, 834, 836 are formedfrom a single tube, for example, a laser-cut tube. In other embodiments,more than one tube may be used to form each of the shafts 832, 834, 836.For example, FIG. 11 illustrates proximal shaft 832 comprising two tubesconnected by welding such as described above.

Referring to FIG. 11A, distal contrast media preferably can be injectedthrough a lumen 854 in the shafts 832, 834 for determining the placementof the intracardiac cage 300. The lumen 854 can be in fluidcommunication with the distal injection port 820, shown in FIGS. 8 and9. The distal shaft 834 preferably includes a mating surface 856 and aradiopaque marker 858. In one embodiment, the mating surface 856 is athreaded surface. The distal shaft 834 preferably is releasably coupledto the intracardiac cage 300 with the slider assembly 406.

Referring back to FIGS. 8 and 9, when the delivery system 800 isassembled, the recapture sheath 804 is preferably loaded over thedeployment catheter 806, distal to the handle 810. The recapture sheath804 preferably is designed to allow recapture of the cage 300 prior toits final release, such as described with respect to retrieval catheterbelow. Recapture petals or flares 860 preferably are provided on thedistal end 862 of the recapture sheath 804 to cover the anchors 318 ofthe cage 300 during retrieval of the cage 300 and re-loading of the cage300 into the transseptal sheath (not shown), as described further below.A Touhy-Borst adapter or valve 864 preferably is attached to theproximal end 866 of the recapture sheath 804. The recapture sheath 804preferably comprises a radiopaque marker 868 on its distal end 862 nearthe recapture flares 860. The recapture sheath 804 preferably comprisesa recapture sheath injection port 870 for delivering fluid proximal thecage 300.

The peel-away sheath 802 preferably is provided over a portion of therecapture sheath 804, between the Touhy-Borst valve 864 and recaptureflares 860. The peel-away sheath 802 preferably is used to introduce thedelivery system 800 into a transseptal sheath, as described in greaterdetail below. As shown in FIGS. 8 and 9, the peel-away sheath 802preferably includes a locking collar 872, a peel-away section 874, and areinforced section 876. The locking collar 872 can be unlocked relativeto the peel-away section 874, and preferably includes a threaded hub 878that releasably engages tabs 880 of the peel-away section 874.

A loading collar 882 (shown in FIG. 9) preferably is located over aportion of the peel-away sheath 802 and a portion of the recapturesheath 804 with its proximal end located over the peel-away sheath 802and its distal end loaded over the recapture sheath 804. The loadingcollar 882 preferably accommodates loading a collapsed cage 300 into thepeel-away sheath 802, as described below. As shown in FIG. 9, theloading collar 882 preferably comprises a first end portion 884 adaptedto receive and extend over a collapsed cage 300, and a second endportion 886 configured to guide the collapsed cage 300 into thepeel-away sheath 802. The loading collar 882 preferably is made ofstainless steel.

System Assembly

To assemble the delivery system 800, the axially movable core 808 andcontrol line 888 preferably are fed into the multi-lumen shaft 812 ofthe deployment catheter 806. The multi-lumen shaft 812 preferably isthen coupled with components of the deployment handle 810 and theinjection ports 818, 820. The peel-away sheath 802 and the loadingcollar 882 preferably are slid onto the recapture sheath 804, and therecapture sheath 804 is slid onto the deployment catheter 806. The cage300 preferably is then loaded on an end of the axially movable core 808and coupled with the control line 888. In one embodiment, the cage 300is loaded on an end of the axially movable core 808 by screwing theaxially movable core 808 into the slider nut 890 of the slider assembly406. The control knob 814 and outer casing of the deployment handle 810preferably are then coupled with the delivery system 800. FIG. 12illustrates one embodiment of an intracardiac cage 300 mounted to thedistal end of a deployment catheter 308.

Transseptal Sheath

The delivery system 800 preferably is used in connection with atransseptal sheath 900, as illustrated in FIGS. 13A-13C, to advance thecage 300 for deployment in a patient. As shown in FIGS. 13A-13C, thetransseptal sheath 900 is a tubular device that in one embodiment can beadvanced over a guidewire (not shown) for accessing a chamber of apatient's heart 100. In one embodiment, the transseptal sheath 900 inone embodiment has a bend 902, as shown in FIGS. 13A and 13B. Thetransseptal sheath 900 of FIG. 13C is another transseptal sheath knownto those of skill in the art having an enlarged diameter at its distalend. A hemostasis valve 904 is provided at the proximal end oftransseptal sheath 900. A fluid injection port 906 is also provided atthe proximal end to delivery fluid (such as contrast media) through thetransseptal sheath 900. Systems and methods for implanting the cage 300in a patient's heart 100 are described in greater detail below.

Crossing the Interatrial Septum

In some cases, a hole or defect exists in the atrial septum 216 of theheart 100. The hole or defect may be used in certain embodiments of thepresent invention to deliver an intracardiac cage 300 to the left atrium104 of the heart 100. In such embodiments, a delivery system 800 isdirected through the hole or defect from the right atrium 114 to theleft atrium 104. In other cases, it is clinically indicated to piercethe septum 216 of the heart 100 with a suitable device, such as adilator, as will be discussed in greater detail below with respect toFIGS. 14-15N.

In one embodiment, a guidewire (not shown) preferably is used to accessthe superior vena cava 202 through groin access. A transseptal sheath900 preferably is advanced over the guidewire and into the superior venacava 202. The guidewire preferably is removed and replaced with atransseptal needle (not shown). The transseptal sheath 900 preferably isretracted inferiorly so that the bend 902 in the transseptal sheath 900directs the distal tip of the transseptal sheath 900 toward the fossaovalis. The needle preferably is advanced to puncture the fossa ovalis.The transseptal sheath 900 preferably is advanced to establish access tothe left atrium 104 and the needle preferably is retracted. Furtherdetails or disclosure are provided in copending U.S. patent applicationSer. No. 09/435,562, filed Nov. 8, 1999 and Ser. No. 10/033,371, filedOct. 19, 2002, published as U.S. Publication No. 2002/0111647, theentireties of which are hereby incorporated by reference.

Dilator

FIGS. 14 and 14A show a dilator 910 in accordance with one embodiment ofthe present invention for accessing the left atrium 104 of the heart 100via the right atrium 114. The dilator 910 has a proximal end 912, adistal end 914, and an elongate flexible tubular body 916. The overalllength of the dilator 910 depends upon the percutaneous access point andthe desired application. For example, lengths in the area of from about80 cm to about 100 cm are typical for use in percutaneous transluminalaccess at the femoral vein for locating and puncturing a site on theatrial septum in the heart.

The tubular body 916 may be manufactured in accordance with any of avariety of known techniques, for manufacturing catheters adapted toreach the coronary arteries or chambers of the heart. For example, thetubular body 916 may be manufactured as an extrusion of appropriatebiocompatible polymeric materials such as high/low density polyethylene(HDPE/LDPE), polytetrafluoroethylene (PTFE), nylons, and a variety ofothers which are known in the art. Blended materials may also be used,such as HDPE (e.g., HDPE/LDPE ratios such as 50%:50%, 60%:40% andothers) with from about 5% to about 25%, and, in one embodiment, about20% BaSO.sub.4 for lubricity and radiopacity. Alternatively, at least aportion or all of the length of tubular body 916 may comprise a springcoil, solid walled hypodermic needle tubing (e.g., stainless steel, NiTialloys) or braided reinforced wall as is understood in the catheter andguidewire arts.

For most applications, the tubular body 916 is provided with anapproximately circular cross sectional configuration having an outsidediameter within the range of from about 0.020″ to about 0.300″. Inaccordance with one embodiment of the invention, the tubular body 916has an outside diameter of about 0.160″ throughout its length. Otherlengths and diameters may be readily utilized, depending upon thedesired profile and performance characteristics.

The proximal end 912 is provided with a manifold 918, having one or moreaccess ports as in known in the art. In the illustrated embodiment,manifold 918 is provided with a core wire port 920 which may also oralternatively function as a guidewire port in an over the wireembodiment. An injection port 922 may also be provided, for injecting acontrast media, such as to confirm that the distal end 914 has traversedthe intraatrial septum 216. Additional access ports may be provided asneeded, depending upon the functional capabilities of the catheter. Themanifold 918 may be injection molded from any of a variety of medicalgrade plastics or formed in accordance with other techniques known inthe art.

The flexible body 916 is provided with a preset bend 924, for assistingin biasing the distal end 914 against the intraatrial septum 216 as isunderstood in the art. The bend 924 preferably has a radius within therange of from about 0.5 cm to about 5 cm and, in one embodiment, about2.5 cm. The bend 924 is centered on a point which is within the range offrom about 1 cm to about 10 cm proximally from distal end 914. In oneembodiment, the bend 924 is centered at approximately 6 cm proximallyfrom distal end 914. The bend 924 can be defined by a proximaltransition where it meets the substantially linear proximal portion ofthe dilator 910, and a distal transition where it meets thesubstantially linear distal portion of the dilator 910. The angulardeflection of the bend 924 is generally within the range of from about30.degree. to about 80.degree. and, in one embodiment, is about50.degree.

The bend 924 may be provided in accordance with any of a variety oftechniques. For example, when the tubular body 916 includes a hypotubeor other metal tubing, it may be bent such as around a forming mandrelin excess of the elastic limit of the hypotube. Alternatively, aninjection molded catheter body may be heat set in a predetermined bend,such as with removable flexible mandrels extending through any interiorlumen to maintain patency of the lumen around the bend 924. Othertechniques will be known to those of skill in the art. Alternatively,the bend 924 may be formed during or after placement of the catheter inthe heart. This may be accomplished by providing the dilator 910 withany of a variety of steering mechanisms, which allow a distal portion914 of the dilator 910 to be inclined away from the axis of the normalbias of the dilator 910. For example, one or more axially moveable pullwires may extend throughout the length of the dilator 910. Proximaltraction on a pull wire that is secured at the distal end 914 of thedilator 910 will cause a lateral defection of the dilator 910.

The dilator 910 is additionally provided with a tissue piercingstructure 926 such as a needle 928. The needle 928 preferably includes atubular structure such as a stainless steel hypotube having a sharpeneddistal end 930. The sharpened distal end 930 of the needle 928 isaxially moveable and advanceable through an aperture 932 in the distalend 914 of the tubular body 916.

In one embodiment, the needle 928 has an axial length of from about 1 cmto about 5 cm, an inside diameter of about 0.022 inches and an outsidediameter of about 0.032 inches. Any of a variety of other dimensions forneedle 928 may also be used depending upon the desired performance andoverall catheter dimensions. The needle 928 is coupled to a controlelement such as core wire 934 which axially moveably extends throughoutthe length of tubular body 916. The proximal end of the core wire 934 inthe illustrated embodiment extends proximally from the core wire port920. The needle 928 is preferably axially moveable between a firstposition in which the tip 930 is contained within the distal end 914 ofthe tubular body 916 and a distal position in which the tip 930 of theneedle 928 is exposed beyond the distal end of the tubular body 916,such as for piercing the fossa ovalis. Distal advancement of theproximal end of the core wire 934 will advance the needle 928 from thefirst position to the second position as will be appreciated in view ofthe disclosure herein. In addition, the needle 928 and core wire 934 maybe removed entirely from the dilator 910, except when desired to piercethe septum. Other mechanisms known to those of skill in the art, such asspring-loaded needles with trigger releases, may be used to move theneedle 928 from the first position to the second position.

Once the piercing structure 926 has pierced the fossa ovalis or otherstructure, and the distal end 914 of the dilator 910 is advanced throughthe opening formed by the piercing structure, the piercing structure 926may be proximally retracted and removed from the dilator 910, therebyleaving the central lumen of the dilator 910 fully available forsubsequent therapeutic or diagnostic devices or materials.

Preferably, the distal end 914 of the dilator 910 is provided with atapered frustro conical surface 936. This allows the tubular body 916 tofunction as a dilator, thereby permitting the tapered surface 936 toenlarge the opening formed by needle 928 while minimizing “tenting” ofthe fossa ovalis during a transseptal access procedure.

Piercing the Interatrial Septum

In accordance with embodiments of the present invention as illustratedin FIGS. 15A-15N, the right atrium 114 may be initially accessed with atransseptal access system through either the inferior or superior venacava 204, 202, which initially involves cannulation with an introducersheath such as through the well known “Seldinger” technique. Atransseptal access system of the present invention includes atransseptal sheath 900, a piercing dilator catheter 910 as discussedabove, and an appropriately sized guidewire 940.

One access point is along the right femoral vein, although access fromthe left femoral vein is also possible. Access may also be achievedthrough a puncture in any of a variety of other veins of suitableinternal diameter and the present invention is not limited in thisregard.

A conventional spring tipped guidewire 940 is thereafter advancedthrough the needle into the vein and the needle is subsequently removed.The dilator 910 is positioned within a sheath such as a 14 Frenchintroducer sheath. Subsequently, the sheath and inner dilator 910, incombination with the guidewire 940, are advanced through the femoralvein to the right atrium 114.

FIG. 15A illustrates a schematic partial cross-section of a portion ofthe heart 100.

The right atrium 114 is in communication with the inferior vena cava 204and the superior vena cava 202. The right atrium 114 is separated fromthe left atrium 104 by the interatrial septum 216. The fossa ovalis 942is located on the interatrial septum 216. As seen in FIG. 15A, thesheath 900 having the dilator 910 and guidewire 940 therein areinitially positioned within the right atrium 114.

The guidewire 940 is then distally advanced to access the superior venacava 202, as shown in FIG. 15B. The dilator 910 and sheath 900 areadvanced into the superior vena cava 202, as illustrated schematicallyin FIG. 15C. The guidewire 940 is proximally retracted.

When the sheath 900 and dilator 910 are in the superior vena cava 202and the guidewire 940 has been removed, the transseptal needle 928 isadvanced through the central lumen of the dilator 910 and sheath 900.The transseptal needle 928 is advanced (possibly with a stylet in place)to a point that the stylet tip is just inside the distal tip of thesheath 900 and dilator 910, a position previously noted by the operator,and the stylet is withdrawn from the transseptal needle 928.

The remaining combination of the sheath 900 with the dilator 910 havingthe transseptal needle 928 therein, is then drawn proximally from thesuperior vena cava 202 while the preset curves 902, 924 at the distalregion of sheath 900 and dilator 910 cause the tip of thesheath-dilator-transseptal needle combination to “drag” along the wallof the right atrium 114 and septum 216, as shown in FIG. 15D, until thedesired penetration location, such as the fossa ovalis 942, is reached.

The tip of the dilator 910 is then positioned against the septum 216 bydistal advancement through the sheath 900. The tip is then dragged alongthe septum 216 by proximal traction on the dilator 910 until the tippops onto the fossa ovalis 942. Various methods and devices known tothose of skill in the art may be utilized to help identify the locationof the fossa ovalis. 942. One such method and device is described inU.S. application Ser. No. 10/100,270, filed, Mar. 15, 2002, published asU.S. Publication No. 2002/0169377, which is incorporated by referenceherein.

The physician is normally assisted during placement, as in the entireprocedure, by fluoroscopy or other visualization techniques. To assistin such visualization, the distal tip of sheath 900 and the distal tipof dilator 910 may be provided with a radiopaque marker. In addition,some physicians find it desirable to infuse a radiopaque dye through thetransseptal needle 928 at various stages of the procedure to assist invisualization, particularly following the transseptal puncture.

After the tip of the sheath-dilator-transseptal needle combination hasbeen placed in the desired location against the fossa ovalis 942, thetransseptal needle 928 is abruptly advanced to accomplish a quickpuncture, as illustrated in FIG. 15E. Immediately after the puncture,one medical technique is to confirm the presence of the tip 930 of thetransseptal needle 928 within the left atrium 104. Confirmation of thelocation of the tip 930 of the transseptal needle 928 may beaccomplished by monitoring the pressure sensed through the transseptalneedle lumen to ensure that the measured pressure is within the expectedrange and has a waveform configuration typical of left atrial pressure.Alternatively, proper position within the left atrium 104 may beconfirmed by analysis of oxygen saturation level of the blood drawnthrough the transseptal needle 928; e.g., aspirating fully oxygenatedblood. Finally, visualization through fluoroscopy alone, or incombination with the use of dye, may also serve to confirm the presenceof the tip 930 of the transseptal needle 928 in the left atrium 104.

Alternatively, if the septum 216 includes a hole or defect, such as apatent foramen ovale, the method of the embodiment illustrated in FIGS.15F-15G may be used. Referring to FIG. 15F, a sheath 900 that includes adilator 910 (not shown) is positioned adjacent the patent foramen ovale944. The patent foramen ovale 944 generally includes a septum secundum946 and a septum primum 948. Additional devices and methods for piercingthe septum primum and secundum are shown in U.S. application Ser. No.10/972,635, filed Oct. 25, 2004, published as U.S. Publication No.2005/0119675, which is incorporated by reference in its entirety.

The transseptal sheath 900 and dilator 910 are positioned adjacent tothe patent foramen ovale 944 and its tissue piercing structure 926 isadvanced distally through the septum secundum 946 and septum primum 948by actuating an actuator, such as a control on the dilator 910 manifold918. In some embodiments, the tissue piercing structure 926 may beadvanced across the septa manually. In other embodiments, tissuepiercing structure 926 may be advanced across the septa using a springloaded handle. Crossing the septa quickly using a spring loaded handlemay facilitate crossing of the septum primum 948.

After placing the transseptal needle tip 930 within the left atrium 104,the tip 936 of the dilator 910 is advanced through the septum 216 andinto the left atrium 104, as shown in FIG. 15H. Typically, care is takento ensure that, at the same time of advancing the dilator 910 and sheath900 into the left atrium 104, the tip 930 of the transseptal needle 928is not advanced a sufficient distance such that the needle 928 candamage the inside wall of the left atrium 104. When the tapered tip 936of the dilator 910 appears to have entered the left atrium 104, thetransseptal needle 928 is withdrawn. The sheath 900 is then advancedinto the left atrium 104, either by advancing the sheath 900 alone overthe dilator 910 or by advancing the sheath 900 and dilator 910 incombination, as shown in FIG. 15I. The dilator 910 is then withdrawnfrom sheath 900, as shown in FIG. 15J. The main lumen of the sheath 900is now available as a clear pathway to advancing further diagnostic ortherapeutic instruments into the left atrium, such as the deliverysystem 800 described in greater detail above with respect to FIGS. 8-12.

After preparing a transseptal sheath 900 for left atrial 104 access, thesize and morphology of the left atrium 104 can be determined byinjecting contrast media through the sheath 900 and into the left atrium104.

In one embodiment, the system and method preferably allows for selectionand preparation of a deployment system 800. The delivery system 800preferably comprises an intracardiac cage 300 of an appropriate size forplacement in a patient. Initially, the cage 300 preferably is in anexpanded configuration, with its axially moveable core 808 engaging aslider assembly 406, as described above. A recapture sheath 804preferably is positioned so it covers and supports the flexible segment850 of the delivery system 800, wherein the flexible catheter section828 of deployment catheter 806 and flexible core section 836 of axiallymoveable core 808 are aligned. The Touhy-Borst valve 864 preferably istightened over the deployment catheter 806 to prevent relative movementbetween recapture sheath 804 and deployment catheter 806. The loadingcollar 882 and peel-away sheath 802 preferably are positioned so theyare at the base of the recapture flares 860, proximal thereto.

The delivery system 800 preferably is loaded by rotating the controlknob 814 counterclockwise until the cage 300 is fully collapsed.Preferably, at least a portion of the control line 888 is coupled withthe control knob 814 such that rotation of the control knob 814 in thecounterclockwise direction retracts at least a portion of the controlline 888. Retraction of the control line 888 preferably places tensionon the proximal hub 308 of the cage 300 because a portion of the controlline 888 preferably is coupled with the proximal hub 308 by a pin 404.While the distal portion of the axially moveable core 808 engages theslider assembly 406 and applies a distal force to distal hub 310 of thecage 300, tension in the control line 888 preferably causes the proximalhub 308 of the cage 300 to move proximally relative the axially moveablecore 808, thereby collapsing the intracardiac cage 300.

The diameter of the cage 300 preferably is reduced to approximately⅓.sup.rd or less of its original diameter when collapsed. The loadingcollar 882 and peel-away sheath 802 are then advanced distally over theflares 860 and cage 300 until the distal tip of the cage 300 is alignedwith the distal end of the peel-away sheath 802 and the distal end ofthe loading collar 882 is about 1.5 cm from the distal tip of the cage300. At this point, the flares 860 partially cover the cage 300. Theloading collar 882 preferably is removed and discarded.

With the cage 300 partially within the recapture sheath 804 andretracted within the peel-away sheath 802, the entire system preferablyis flushed with sterile heparinized saline after attaching stopcocks tothe recapture sheath injection port 870, the proximal injection port 818and distal injection port 820 of the delivery system 800. The recapturesheath 804 and the Touhy-Borst valve 864 are first thoroughly flushedthrough port 870. The distal injection port 818 and the proximalinjection port 820 of the deployment handle 810 are preferably flushedas well. The distal injection port 820 is in fluid communication withlumen 854 of the axially moveable core 808, and the proximal injectionport 818 is in fluid communication with injection lumens 826 of themulti-lumen shaft 812. The transseptal sheath 900 placement preferablyis reconfirmed using fluoroscopy and contrast media injection.

The delivery system 800, as described above, with the cage 300 coupledthereto, preferably is then inserted into the proximal end of thetransseptal sheath 900. To avoid introducing air into the transseptalsheath 900 during insertion of the delivery system 800, a continual,slow flush of sterile heparinized saline preferably is applied throughthe proximal injection port 818 of the deployment handle 810 to thedistal end of the deployment catheter 806 until the tip of the peel-awaysheath 802 has been inserted into, and stops in, the hemostatic valve904 of the transseptal sheath 900. Preferably, the distal tip of thepeel-away sheath 802 is inserted approximately 5 mm relative to theproximal end of the transseptal sheath 900.

Under fluoroscopy, the recapture sheath 804 and deployment catheter 806preferably are advanced, relative to the peel-away sheath 802,approximately 20-30 cm from the proximal end of the transseptal sheath900, and the system 800 preferably is evaluated for trapped air. Thepeel-away sheath 802 is preferably not advanced into the transseptalsheath 900 due to the hemostasis valve 904 blocking its passage. If airis present in the system 800, it may be removed by aspirating throughthe distal injection port 820, recapture sheath injection port 870, orproximal injection port 818. If air cannot be aspirated, the deploymentcatheter 806 and recapture sheath 804 preferably are moved proximallyand the delivery system 800 preferably is removed from the transseptalsheath 900. All air preferably is aspirated and theflushing/introduction procedure preferably is repeated.

The peel-away sheath 802 preferably is manually slid proximally to theproximal end 866 of the recapture sheath 804. The Touhy-Borst valve 864preferably is loosened and the deployment catheter 806 preferably isadvanced distally relative to the recapture sheath 804 until thedeployment handle 810 is within about 2 cm of the Touhy-Borst valve 864of the recapture sheath 804. This causes the cage 300 to be advanceddistally within the transseptal sheath 900 such that the recapturesheath 804 no longer covers the cage 300 or the flexible section 850.The Touhy-Borst valve 864 preferably is tightened to secure thedeployment catheter 806 to fix relative movement between the deploymentcatheter 806 and recapture sheath 804.

Under fluoroscopy, the cage 300 preferably is advanced to the tip of thetransseptal sheath 900 by distal movement of the deployment catheter806. The distal hub 310 of the cage 300 preferably is aligned with atransseptal sheath 900 tip radiopaque marker 950, as illustrated in FIG.13A. Under fluoroscopy, the sheath 900 position within the left atrium104 preferably is confirmed with a distal contrast media injection. Thedistal end of the transseptal sheath 900 is positioned at, near, orinside of the ostium of the left atrial appendage 106, as illustrated inFIG. 15K.

The position of the cage 300 preferably is maintained by initiallyholding the deployment handle 810 stable. The transseptal sheath 900preferably is withdrawn proximally until its tip radiopaque marker 950is within about 1-2 mm of the septum 216 but still within the leftatrium 104. This preferably exposes at least a portion of the cage 300,as shown in FIG. 15L.

Under fluoroscopy, the cage 300 preferably is expanded at least in partby rotating the control knob 814 clockwise. Rotating the control knob814 preferably releases tension on the control line 888, preferablyallowing the cage 300 to expand, as illustrated in FIG. 15M. At thispoint, the sheath 900 is advanced until the cage 300 abuts the vicinityof the left atrial appendage 106. The cage 300 is then deployed a littlemore. Sheath 900 advancement and cage 300 deployment and expansion isrepeated until the cage 300 is fully deployed out of the sheath 900. Thecage 300 preferably is self-expanding. After expansion, any tension onthe left atrial appendage 106 or left atrium 104 preferably is removedby carefully retracting the deployment handle 810 under fluoroscopyuntil the radiopaque marker 858 on the axially movable core 808 movesproximally approximately 1-2 mm in the guide tube of the slider assembly406. The position of the cage 300 relative the left atrial appendage 106and left atrium 104 preferably is not altered because the axiallymovable core 808 preferably is coupled with the slider assembly 406,which allows for relative movement between the cage 300 and the axiallymovable core 808. The slider assembly 406 preferably allows for thedistal portion of the axially movable core 808 to be slightly retractedproximally from the distal hub 310 of the cage 300, thereby removing anyaxial tension that may be acting on the cage 300 through the axiallymovable core 808. The radiopaque marker 858 preferably is about 1-2 mmproximal from the cage 300 distal hub 310, and the transseptal sheath900 tip preferably is about 2-3 mm proximal from the implant proximalhub 308, thereby indicating a neutral position.

In one embodiment, the cage 300 is positioned within the left atrium 104such that the barrier 500B covering its distal end 304 is aligned withthe ostium of the left atrial appendage 106. In another embodiment, thecage 300 is positioned within the left atrium 104 such that the barrier500A covering its proximal end 302 is aligned with a portion of theseptum 216, such as a patent foramen ovale 944. In yet anotherembodiment, the cage 300 is positioned within the left atrium 104 suchthat the barrier 500B covering its distal end 304 is aligned with theostium of the left atrial appendage 106 and the barrier 500A coveringits proximal end 302 is aligned with a portion of the septum 216, suchas a patent foramen ovale 944.

Under fluoroscopy, the expanded diameter of the cage 300 preferably ismeasured in at least two views to assess the position of the implantwithin the left atrium 104. The measured implant diameter preferably iscompared to the maximum expanded diameter.

Preferably, the proximal and distal injection ports 818, 820 of thedeployment handle 810, correlate with the proximal and distal contrastmedia injections. The proximal contrast media injections are deliveredthrough the delivery catheter lumen 826 to a location proximal to thecage 300. The distal contrast media injections are delivered through theaxially movable core 808 to a location distal to the cage 300. Proximalcontrast media injections preferably are completed in two views. If theinjection rate is insufficient, the recapture sheath injection port 870may be used independently or in conjunction with the proximal injectionport 818 to deliver fluid to a location proximal to the cage 300.

If satisfactory results are obtained, any transverse tension on the leftatrial appendage 106 or left atrium 104 preferably is released byexposing the flexible segment 850 of the delivery system 800. Theflexible catheter section 828 and the flexible core section 836preferably are linearly co-located to cooperate as the flexible cathetersection 828 of the delivery system 800, as described above. Thispreferably is accomplished by retracting the transseptal sheath 900proximally approximately 2 cm to expose the flexible section 828. Byexposing the flexible section 828, the flexible section 828 preferablywill flex to allow the cage 300 to sit within the left atrium 104 freefrom transverse forces that may be created, for example, by contractionsof the heart acting against the transseptal sheath 900 or deploymentcatheter 806.

Once the flexible section 828 is exposed, distal contrast mediainjections preferably are completed in at least two views to verifyproper positioning of the cage 300. A flush of saline preferably is usedas needed between injections to clear the contrast media from the leftatrial appendage 106. Following the contrast media injections, thetransseptal sheath 900 preferably is advanced distally to cover theflexible section 828.

Repositioning

If the cage 300 position or results are sub-optimal, the cage 300preferably may be collapsed and repositioned in the left atrium 104. Todo so, under fluoroscopy, the deployment handle 810 preferably isadvanced distally to place the radiopaque marker 858 of the axiallymoveable core 808 at the distal hub 310 of the cage 300. The distal endof the transseptal sheath 900 preferably is aligned with the distal endof the flexible segment 850. The control knob 814 preferably is rotateduntil the cage 300 has been collapsed to approximately ⅓.sup.rd or lessof its expanded diameter. The tip of the transseptal sheath 900 can bewithdrawn into the right atrium 114 during recapture to preventexcessive lengthening of the cage 300 within the left atrium 104 andpotential tissue trauma. The control knob 814 preferably acts on thecontrol line 888 to place tension on the proximal hub 308 of the cage300, pulling the proximal hub 308 of the cage 300 proximally relativethe distal hub 310 of the cage 300 to collapse the cage 300. The cage300 preferably can be repositioned and re-expanded.

The stability of the cage 300 preferably is verified in several views.Stability tests preferably are preformed in the following manner. Acontrast media filled syringe preferably is connected to the distalinjection port 820 of the deployment handle 810. Under fluoroscopy, atleast about a 10 mm gap between the tip of the transseptal sheath 900and the proximal hub 308 of the cage 300 is preferably confirmed.

The stability of the cage 300 in the left atrium 104 preferably isevaluated using fluoroscopy and echocardiography. The recapture sheathTouhy-Borst valve 864 preferably is loosened. Then the deployment handle810 preferably is alternately retracted and advanced about 5-10 mm whilemaintaining the position of the transseptal sheath 900 andsimultaneously injecting contrast media through the distal injectionport 820. This tests how well the implant is held within the left atrium104.

If the implant stability tests are unacceptable, the cage 300 preferablymay be collapsed and repositioned as described above. If repositioningthe cage 300 does not achieve an acceptable result, the cage 300preferably may be collapsed and recaptured as described further below.

The cage 300 preferably meets the following acceptance criteria,associated with the assessment techniques listed below, prior to beingreleased. The assessment techniques to be evaluated preferablyinclude 1) residual compression; 2) implant location; 3) anchorengagement; 4) seal quality; and 5) stability. For residual compression,the implant diameter, as measured by fluoroscopic imaging, preferably isless than the maximum expanded diameter of the cage 300. For implantlocation, the proximal sealing surface of the cage 300 preferably ispositioned between the left atrial appendage 106 ostium and sources ofthrombus formation (pectinates, secondary lobes, etc.) (preferablyimaged in at least two views). For anchor engagement, the cage 300 frame402 preferably is positioned within the left atrium 104 so as to engagea row of anchors or barbs 318 in a left atrial 104 wall (preferablyimaged in at least two views). For seal quality, the contrast injectionspreferably show leakage rated no worse than mild (preferably defined asa flow of contrast media, well defined, and filling one-third of theleft atrial appendage 106 during a proximal injection over a period ofup to about five ventricular beats, preferably imaged in at least twoviews). For stability, there preferably is no migration or movement ofthe cage 300 relative to the left atrium 104 or septal defect as aresult of the Stability Test, as described above.

Recapture and Retrieval

If cage 300 recapture is desired or necessary (e.g., because a differentsize cage 300 is necessary or desired), or if acceptable positioning orsealing cannot be achieved, the cage 300 preferably is fully collapsedas described above. Once the cage 300 is collapsed, the locking collar872 of the peel away sheath 802 preferably is unlocked. The peel-awayportion 874 of the peel-away sheath 802 preferably is split up to thereinforced section 876 and removed. The reinforced section 876 of thepeel-away sheath 802 preferably is slid proximally to the hub of therecapture sheath 804. The Touhy-Borst valve 864 on the proximal end ofthe recapture sheath 804 preferably is slightly loosened to allow smoothmovement of the recapture sheath 804 over deployment catheter 806without allowing air to enter past the Touhy-Borst valve 864 seal. Byremoving the peel-away portion 874 of peel-away sheath 802, therecapture sheath 804 can now be advanced further distally relative tothe transseptal sheath 900.

While holding the deployment catheter 806 and transseptal sheath 900 inplace, the recapture sheath 804 preferably is advanced distally into thetransseptal sheath 900 until a half marker band 868 on the recapturesheath 804 is aligned with a full marker band 950 on the transseptalsheath 900. This preferably exposes the recapture flares 860 outside thetransseptal sheath 900.

The collapsed cage 300 preferably is retracted into the recapture sheath804 by simultaneously pulling the deployment handle 810 and maintainingthe position of the recapture sheath 804 until approximately half thecage 300 is seated in the recapture sheath 804. The Touhy-Borst valve864 on the recapture sheath 804 preferably is tightened over thedeployment catheter 806. The recapture sheath 804 and cage 300preferably are retracted into the transseptal sheath 900 by pulling onthe recapture sheath 804 while maintaining the position of thetransseptal sheath 900, preferably maintaining left atrial access. Therecapture flares 860 of the recapture sheath 804 preferably cover atleast some of the anchor or barbs 318 on the cage 300 as the cage 300 isretracted proximally into the transseptal sheath 900.

De-Coupling

If the cage 300 position and function are acceptable, and cage 300recapture is not necessary, the cage 300 preferably is released from thedelivery system 800. Under fluoroscopy, the transseptal sheath 900preferably is advanced to the proximal hub 308 of the cage 300 forsupport. The release knob 816 on the proximal end of the deploymenthandle 810 preferably is rotated to release the cage 300. Rotating therelease knob 816 preferably causes a mating surface 856, such as athreaded portion, of the distal shaft 834 of the axially movable core808 to rotate with respect to the slider assembly 406 such that themating surface 856 preferably is decoupled from the slider assembly 406.Under fluoroscopy, after the axially movable core 808 is decoupled fromthe cage 300, the release knob 816 preferably is retracted until thedistal shaft 834 of the axially movable core 808 is at least about 2 cmwithin the transseptal sheath 900.

Under fluoroscopy, while assuring that transseptal access is maintained,the delivery system 800 preferably is retracted and removed through thetransseptal sheath 900. Under fluoroscopy, the transseptal sheath 900position preferably is verified to be approximately 1 cm away from theface of the cage 300. Contrast injections, fluoroscopy and/orechocardiography preferably may be used to confirm proper positioningand delivery of the cage 300 and position with respect to the leftatrial appendage 106 and septum 216. The transseptal sheath 900preferably is withdrawn, as illustrated in FIG. 15N.

When the cage 300 is positioned within the left atrium 104 asillustrated in FIG. 15N, a continuous light pressure is applied to theseptum primum 948 from the left atrial 104 side. The barrier 500A on theproximal face 502 of the cage 300 generally includes an ePTFE laminationor other structure that promotes neointimal growth andendothelialization. As ingrowth and endothelialization occur, anaturally formed barrier to seal, close, or patch a defect in the septum216 is achieved. The cage 300 provides a frame or scaffolding to holdthe barrier 500B in place against the septum 216 and across and/orinside of the left atrial appendage 106, as described in greater detailabove.

One advantage of the intracardiac cage 300 is that gross stretching ordistension of the patent foramen ovale 944 opening do not occur, eitherfor sizing, or because of oblique attachment. Although the intracardiaccage 300 has been primarily described with respect to implantationwithin the left atrium 104, it should be understood by those of skill inthe art that the same or equivalent structures can be used within theright atrium of the heart to provide a barrier 500 against the septumsecundum 946 and/or the ostium of the right atrial appendage 116. Inaddition, the same or similar structures may be used to provide abarrier 500 against any septal defect, whether in the interatrial septumor the interventricular septum. For example, the present invention maybe used to provide a barrier to seal off, block, or filter an atrialseptal defect (ASD), a ventricular septal defect (VSD), a patent foramenovale (PFO), or a patent ductus arteriosis (PDA).

Although throughout this application the term cage has been used, thoseof skill in the art should understand that the terms implant andocclusion device may be used as well to describe identical or equivalentstructures. One of ordinary skill in the art will appreciate that all ofthe disclosures herein are applicable to a wide variety of structuresthat include both cages and implants that may or may not also beocclusion devices. Routine experimentation will demonstrate thoselimited circumstances under which certain disclosures and combinationsthereof are not beneficial.

1. A method of implanting an expandable intracardiac cage into a leftatrium of a heart, comprising: advancing intravascularly a deliverysheath having a delivery sheath proximal end, a delivery sheath distalend, and a lumen extending therebetween to a right atrium of a heart;advancing the delivery sheath distal end through an opening between theright atrium and the left atrium, wherein the delivery sheath distal endcontains an expandable cage having a proximal end, a distal end, and aplurality of supports extending therebetween, wherein the expandablecage has a collapsed configuration sized and adapted to be receivedwithin the lumen of the delivery sheath distal end, and an expandedconfiguration for deployment within the heart; delivering the expandablecage to the left atrium through the delivery sheath; and expanding theexpandable cage within the left atrium, the expandable cage whenexpanded positioning the distal end of the expandable cage adjacent anopening in the wall of the left atrium; and positioning the proximal endof the expandable cage against a wall of the left atrium, wherein theexpandable cage includes a plurality of barbs proximate at least one ofthe distal end or the proximal end of the cage, wherein each barb of theplurality of barbs hold, secure, fix, lock, or maintain a position of animplantable device within the heart wherein the cage is sized andadapted to span a distance between the opening in the wall of the leftatrium and the wall of the left atrium against which the proximal end ofthe expandable cage is positioned to maintain a degree of residualcompression of the expandable cage while the distal end of theexpandable cage and the proximal end of the expandable cage contact thewall of the left atrium.
 2. The method of claim 1, wherein theexpandable cage is self-expanding.
 3. The method of claim 1, wherein theexpandable cage may be collapsed to a collapsed configuration whilemaintaining the distance between the proximal end and the distal end ofthe expandable cage substantially constant.
 4. The method of claim 3,wherein the plurality of supports fold to maintain the distance betweenthe proximal end and the distal end of the expandable cage substantiallyconstant when the cage is collapsed to its collapsed configuration. 5.The method of claim 3, wherein the plurality of supports telescope tomaintain the distance between the proximal end and the distal end of theexpandable cage substantially constant when the expandable cage iscollapsed to its collapsed configuration.
 6. The method of claim 1,wherein the cage is collapsed to its collapsed configuration whilereducing the distance between the proximal end and the distal end of theexpandable cage.
 7. The method of claim 6, wherein the plurality ofsupports fold to reduce the distance between the proximal end and thedistal end of the expandable cage when the expandable cage is collapsedto its collapsed configuration.
 8. The method claim 6, wherein theplurality of supports telescope to reduce the distance between theproximal end and the distal end of the expandable cage when theexpandable cage is collapsed to its collapsed configuration.
 9. Themethod of claim 1, wherein each support of the plurality of supportscomprises a region having a serpentine curve.
 10. The method claim 9,wherein each of the serpentine curve regions is spaced from the proximalend and from the distal end of the cage.
 11. The method of claim 2,wherein at least some supports of the plurality of supports are branchedinto branches which provide mechanical coverage at least one end of thecage.
 12. The method of claim 1, wherein at least some supports of theplurality of supports includes a hinge.
 13. The method of claim 1,wherein when the expandable cage expands from the collapsedconfiguration to the expanded configuration within the left atrium ofthe heart, it expands not only radially outward, but also to increasethe distance between the proximal end of the cage and the distal end ofthe cage.
 14. The method of claim 1, wherein a region including one endof the cage is covered with a membrane or mesh which is occlusive toemboli.
 15. The method of claim 14, wherein the region which is coveredwith a membrane or mesh which is occlusive to emboli is positioned at anostium of the left atrium.
 16. The method of claim 1, wherein a regionincluding one end of the cage is covered with a membrane or mesh whichis occlusive to blood.
 17. The method of claim 16, wherein the regionwhich is covered with a membrane or mesh which is occlusive to blood ispositioned at an ostium of the left atrium.
 18. The method of claim 16,wherein the region which is covered with a membrane or mesh which isocclusive to blood is positioned at fossa ovalis, a septal defect, orthe patent foramen ovale of the left atrium.
 19. The method of claim 1,wherein the distal end of the expandable cage is oriented within theleft atrium in relation to a blood flow pathway such as a pulmonary veinor a mitral valve.
 20. The method of claim 19, wherein the distal end ofthe expandable cage is positioned adjacent the mitral valve.